Answer:
b. A couplet with an end-stopped line.
Explanation:
A couplet is a form of poetry where two successive lines of a poem rhyme at the end. Moreover, the two lines of poetry will have the same meter.
A couplet with an end-stopped line refers to a couplet where the first line will be continued onto the next line. Another identifier of an end-stopped line is if the first line ends with a comma and then the second line ends the sentence with a period/full stop.
Looking at the given line from Alexander Pope's "An Essay on Criticism", the line is an example of a couplet with an end-stopped line. The first line ends with a comma whereas the second line ends with a full stop. Moreover, the end words rhyme with each other, for "chance" and "dance" rhymes.
Thus, the correct answer is option b.